Brown fused alumina is a kind of artificial corundum produced by high temperature smelting of natural bauxite. Although the main component is Aluminium Oxide, it still contains a lot of other chemical components such as silica, iron oxide, titanium oxide, etc. Although these contents will affect the abrasive and refractory properties, but also to a certain extent the application is beneficial, such as titanium oxide can increase its toughness. And these secondary components can not be completely removed.

White Spot refers to the white impurity in brown fused alumina granularity in the smelting process, formed in brown fused alumina. Bauxite mine and smelting process to add iron and anthracite raw material itself will contain various impurities, and chemical reaction will also produce some impurities in high temperature smelting process of electric arc furnace. Among them, the white spots are most visible to the naked eye. These impurities will affect the effective components of brown fused alumina, have a certain impact on the grinding performance and fire resistance, and the appearance is not too beautiful to affect the feelings of the end user. In particular, some of the fine grinding industry which require high standard, these impurities may make the final product defective. It is difficult to completely remove these white impurities, because it is produced in the smelting process, the number of brown fused alumina will have a certain amount of content.